<!DOCTYPE html>
<html lang="zh-cn">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Title</title>
    <script src="./js/02.js"></script>
</head>
<body>
    <h1 class="a">标签</h1>
    <hr>
    <div id="div1">
        <h4>标签</h4>
        <h4 class="a">标签</h4>
        <h4>标签</h4>
    </div>
    <hr>
    <div id="div2">
        <h4>标签</h4>
        <h4 class="a">标签</h4>
        <h4>标签</h4>
    </div>
</body>
</html>